Project description:Diversity of photosynthetic picoeukaryotes in eutrophic shallow lakes as assessed by combining flow cytometry cell-sorting and high throughput sequencing
Project description:Tumorigenic breast cancer cells characterized by CD44 expression and low or undetectable CD24 levels (CD44+/CD24-/low) may be resistant to chemotherapy and therefore responsible for cancer relapse. Paired breast cancer core biopsies before and after neoadjuvant chemotherapy or lapatinib were obtained and as single cell suspensions stained using antibodies against CD24, CD44, and lineage markers, and then analyzed by flow cytometry. Mammosphere (MS) formation in culture was compared before and after treatment. Global gene expression differences between cancer cells bearing CD44+/CD24-/low cells and all other sorted cells, and between cancer MS and the primary bulk invasive cancers were analyzed. We report that CD44+/CD24-/low tumorigenic breast cancer cells were intrinsically chemoresistant â chemotherapy led to increased CD44+/CD24-/low cells, increased self-renewal capacity on MS assays, and enhanced tumorigeneicity in immunocompromised SCID/Beige mice. Conversely, in patients with HER2 overexpressing tumors, the EGFR/HER2 tyrosine kinase inhibitor, lapatinib decreased CD44+/CD24-/low cells, with the majority of these patients after conventional therapy achieving pathologic complete response, a validated surrogate marker for long-term survival. Gene transcription pathways that underlie chemoresistant, MS-forming CD44+/CD24-/low cells involve genes belonging to stem cell self-renewal, Wnt signaling, and early development pathways. Experiment Overall Design: Human breast tumor samples were sorted using flow cytometry to select for cells that were CD44+ and CD24-. Gene expression profiles of these cells were compared with profiles of the other sorted cells (CD24+ and CD44-/CD24-). Experiment Overall Design: Core biopsies of primary breast tumors were taken and placed immediately in cold RPMI-1640 supplemented with 10% heat-inactivated newborn calf serum (HINCS, Invitrogen, Carlsbad, CA). Within an hour, the samples were minced and then digested in 10-15 mL of MEGM with 250-300 units/mL collagenase at 370C. The samples were filtered, washed, and then subjected to hypotonic shock to lyse red blood cells. About 106 single cells were re-suspended, incubated for 15 min at 40C with anti-CD44 (APC), anti-CD24 (FITC), and anti-lineage cocktail antibodies (PE-conjugated anti-CD2, CD3, CD10, CD16, CD18, CD31 and CD 140B) (Pharmingen, San Diego, CA) using the manufacturerâs suggested concentrations. The cells were then washed twice, re-suspended with the viability dye propidium iodide, and analyzed using Dako MoFlo flow cytometry. Side- and forward- scatter were used to eliminate debris and cell doublets, and the Lin- cells were further analyzed by CD44 and CD24 markers.
Project description:This study was designed to investigate the efficacy of flow cytometry to accurately identify between normal and cancer cells in colon epithelium in humans diagnosed with colorectal cancer.
Project description:Midbrain organoid derived from human induced pluriopotent stem cells a new model of Parkinson's Disease. Organ specific organoids can be used to model many diseases, however little is know about these models. We created a flow cytometry workflow to identify cell types in midbrain organoids. We then selected four populations and sorted these populations: Neurons1(CD24++), Neurons2(CD56++), Astrocytes and Radial Glia, using FACS and the antibody intensity gates defined by our workflow. We then performed scRNAseq on the sorted population and identified cell types within the sorted populations.
Project description:Proteins contribute to the structure of chromatin and regulate its functions. The basic building block of chromatin in eukaryotes is the nucleosome containing histones. Structural maintenance of chromosomes complexes perform the assembly of genomic DNA into the higher organizational structures of interphase chromatin as well as the compact arrangement of dividing chromosomes. Here, proteins were extracted from flow cytometry-sorted barley mitotic chromosomes after a nuclease treatment to remove DNA. Peptides from tryptic protein digests were fractionated either on a cation exchanger or reversed-phase microgradient system prior to liquid chromatography coupled to tandem mass spectrometry. Nuclear and chromosomal proteins (almost 900 identifications) were then classified based on a combination of software prediction results, available database localization information, sequence homology, and domain representation. The degree of enrichment of the chromosome samples by chromosomal proteins was evaluated by comparing the results with controls (depleted flow cytometric fraction and initial cell lyzate). A biological context evaluation indicated the presence of several groups of abundant proteins including histone variants, topoisomerase 2, PARP2, Condensin complex subunits, and many proteins with chromatin-related functions. Interestingly, nucleolar proteins were found as wells as proteins documenting processes related to replication, transcription and DNA repair in barley mitotic chromosomes.
Project description:We report the transcriptomic differences between ASPcKO and ASPcKOP7cKO flow cytometry-sorted FN-RMSs by RNA sequencing. The goal of this study is to determine what role Pax7 loss has on Pten-deficient, Hedgehog-activated murine FN-RMS tumors. These results provide implications for the transcriptomic program driven by Pax7 in dictating FN-RMS tumor fate.